1. Field of the Invention
The present invention relates to an ultrasonic diagnostic apparatus wherein ultrasonic waves are transmitted to an object to be inspected and echo waves reflected from the object are received so that a medical diagnosis is made on the basis of an image obtained from information contained in the received echo waves.
2. Description of a Related Art
In general, the qualities of an ultrasonic diagnostic image depend on the transmission/reception conditions of ultrasonic waves, the processing conditions of the image, etc. As the ultrasonic transmission/reception conditions, a center frequency, a bandwidth, a focussing position, transmission power, reception sensitivity, etc. of the ultrasonic waves are mentioned. As the image processing conditions, brightness and contrast in an image displayed on a display device are mentioned. Regarding these conditions, appropriate values would exist for every body part of an object to be inspected.
Heretofore, the parameters of the ultrasonic transmission/reception conditions and image processing conditions, etc. have been manually input from an operation panel mounted on the ultrasonic diagnostic apparatus, and they have been reset and optimized each time when an image has been obtained and displayed. Adjustments for such optimization of the parameters must be made while the object is being scanned with an ultrasonic probe, and they are very laborious and troublesome operations for a person such as a doctor who handles the ultrasonic diagnostic apparatus.
Meanwhile, Japanese patent application publication (post examination) JP-B-2-21262 discloses an ultrasonic diagnostic apparatus in which the maximum value and minimum value of an ultrasonic echo signal are detected, and the ultrasonic image of any designated body part is displayed by automatically changing the gradation from the zero gradation to the maximum gradation on the basis of the detected values. However, a gradation control process proper for each individual body part can not be executed merely by automatically changing the gradation of the ultrasonic image indiscriminately from the zero gradation to the maximum gradation.
It is also considered to preset nearly appropriate conditions for every body part of the object to be inspected, and to set the transmission/reception conditions and the image processing conditions on the basis of the preset conditions and analytical information obtained from the image. According to this technique, the ultrasonic image can be displayed by employing the appropriate transmission/reception conditions and image processing conditions for each image. However, since the analysis of the image is made within a predetermined image region, the determined conditions might deviate from the optimum conditions when a region desired to be observed is somewhat discrepant from the analyzed region.
In this regard, Japanese patent application laid-open JP-A-5-240919 discloses a radiation image reproduction apparatus wherein an image signal expressive of a radiation image is reproduced through image processing. According to the apparatus, when a desired region of interest (ROI) is set on the radiation image, the image processing of the radiation image within the region can be executed by a simple operation. However, the radiation image reproduction apparatus executes the image processing for static image data already acquired, and the technique does not cope with a system which acquires and displays a dynamic image as in the ultrasonic diagnostic apparatus.
Besides, Japanese patent application laid-open JP-A-6-205780 discloses an ultrasonic image processing apparatus in which the degree of the contrast of a region of interest is searched for, and contrast intensification suited to the region can be always effected. However, a gradation control process proper for each individual body part cannot be executed merely by executing the contrast intensification process indiscriminately in the region of interest.